PA-11-261 (NIH Exploratory/Developmental Research Grant Program): One-quarter to one-third of all elderly nursing home residents in the US receive antipsychotic drugs despite extensive data demonstrating marginal clinical benefits and serious adverse effects including death adults. High use persists despite over a decade of federal intervention. Understanding where antipsychotics are first prescribed is critical for ameliorating this public health problem. Recently, we documented that nearly half of residents on antipsychotics in the nursing home initiate therapy before the nursing home admission. Over 1/3 of all nursing admissions come directly from hospital transfers and the risk of being hospitalized in a 6 month period for nursing home residents is ~25%. As a result, a nontrivial number of hospitalized older adults are transferred to nursing homes already initiated on antipsychotics for reasons that are unknown to the nursing home staff. Our review of the literature revealed no studies on the relationship between the hospital setting and antipsychotic use in nursing homes. We will use a large contemporary data source (Cerner HealthFacts) on the inpatient care and medications prescribing of elderly patients discharged to nursing home from~230 hospitals geographically dispersed throughout the US (n=~1,200,000 elderly patients discharged to nursing homes in 2011-2012). The specific aims are: 1) To estimate the prevalence and incidence of antipsychotic use among elderly patients in a general hospital setting and evaluate the extent to which patient level factors associated with antipsychotic use identified in the nursing home setting are correlates of use in the hospital; 2) To examine hospital level variation in antipsychotic use in-hospital settings among older adults; 3) To develop and test a multilevel model explaining variation in in-hospital antipsychotic use as a function of patient level, organizational level and community level factors. We hypothesize that NH residents not on antipsychotics when admitted for an acute care hospitalization are frequently discharged back to the NH on antipsychotics, that Antipsychotics initiated in the hospital for acute and reversible indications such as delirium are often not discontinued upon discharge from the hospital when the indication may have resolved, and that hospital level variation in antipsychotic prescribing patterns will exist and similar correlates of use (patient, organizational, and community) as observed in the nursing home context will be observed in hospitals. Despite the ~2.2 million elderly hospital patients discharged from hospital to NHs each year, no studies (to our knowledge) have examined the initiation of antipsychotics among elderly patients in hospitals. This study will provide a novel area of exploration for future interventions to ultimately reduce antipsychotic use in older adults.